Method and apparatus for uplink ACK/NACK resource allocation

ABSTRACT

A method is provided to allocate resources for wireless communications. The method includes grouping downlink control channels from multiple subframes and ordering the downlink control channels across downlink subframes having a first control channel element located in a first symbol map and associated with reserved resources for an uplink channel. The method employs a symbol first mapping or a mixed-symbol/subframe first mapping to efficiently allocate the resources.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. Ser. No. 12/433,678, filedApr. 30, 2009, entitled: METHOD AND APPARATUS FOR UPLINK ACK/NACKRESOURCE ALLOCATION, which claims the benefit of U.S. Provisional Ser.No. 61/049,827, entitled METHODS OF UL ACK/NACK RESOURCE ALLOCATION FORTDD IN E-UTRAN, filed on May 2, 2008, the entirety of which are bothincorporated herein by reference.

BACKGROUND

I. Field

The following description relates generally to wireless communicationssystems, and more particularly to efficiently allocating resources viaflexible symbol mapping methods.

II. Background

Wireless communication systems are widely deployed to provide varioustypes of communication content such as voice, data, and so forth. Thesesystems may be multiple-access systems capable of supportingcommunication with multiple users by sharing the available systemresources (e.g., bandwidth and transmit power). Examples of suchmultiple-access systems include code division multiple access (CDMA)systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, 3GPP Long Term Evolution (LTE)systems including E-UTRA, and orthogonal frequency division multipleaccess (OFDMA) systems.

An orthogonal frequency division multiplex (OFDM) communication systemeffectively partitions the overall system bandwidth into multiple(N_(F)) subcarriers, which may also be referred to as frequencysub-channels, tones, or frequency bins. For an OFDM system, the data tobe transmitted (i.e., the information bits) is first encoded with aparticular coding scheme to generate coded bits, and the coded bits arefurther grouped into multi-bit symbols that are then mapped tomodulation symbols. Each modulation symbol corresponds to a point in asignal constellation defined by a particular modulation scheme (e.g.,M-PSK or M-QAM) used for data transmission. At each time interval thatmay be dependent on the bandwidth of each frequency subcarrier, amodulation symbol may be transmitted on each of the N_(F) frequencysubcarrier. Thus, OFDM may be used to combat inter-symbol interference(ISI) caused by frequency selective fading, which is characterized bydifferent amounts of attenuation across the system bandwidth.

Generally, a wireless multiple-access communication system canconcurrently support communication for multiple wireless terminals thatcommunicate with one or more base stations via transmissions on forwardand reverse links. The forward link (or downlink) refers to thecommunication link from the base stations to the terminals, and thereverse link (or uplink) refers to the communication link from theterminals to the base stations. This communication link may beestablished via a single-in-single-out, multiple-in-signal-out or amultiple-in-multiple-out (MIMO) system.

A MIMO system employs multiple (NT) transmit antennas and multiple (NR)receive antennas for data transmission. A MIMO channel formed by the NTtransmit and NR receive antennas may be decomposed into NS independentchannels, which are also referred to as spatial channels, whereN_(S)≦min {N_(T), N_(R)}. Generally, each of the NS independent channelscorresponds to a dimension. The MIMO system can provide improvedperformance (e.g., higher throughput and/or greater reliability) if theadditional dimensionalities created by the multiple transmit and receiveantennas are utilized. A MIMO system also supports time division duplex(TDD) and frequency division duplex (FDD) systems. In a TDD system, theforward and reverse link transmissions are on the same frequency regionso that the reciprocity principle allows estimation of the forward linkchannel from the reverse link channel. This enables an access point toextract transmit beam-forming gain on the forward link when multipleantennas are available at the access point.

One consideration in the deployment of the above systems relates to howresources are allocated during downlink communications. Resources aretypically generated within the context of a resources block andgenerally consume multiple subcarriers. Thus, the conservation ofresource block generation and transmission is a desired feature ofwireless communications. One area where such resources are consumed isin the support of multiple acknowledgements (ACK) during an uplink (UL)handshake sequence, where the handshake is in response to a downlink(DL) subframe transmission. The UL transmissions can also includenegative acknowledgement (NACK) as well, thus the term ACK/NACK is oftenemployed. In a frequency division duplex (FDD) scenario, the number ofresources is controlled since there is an implicit one-to-one resourcemapping between UL and DL subframe transmissions. In a time divisionduplex (TDD) scenario however, there can be asymmetric differencesbetween the number of DL subframes and respective UL subframes. Suchasymmetries can cause an inefficient allocation of resources however ifa one-one mapping is assumed.

SUMMARY

The following presents a simplified summary in order to provide a basicunderstanding of some aspects of the claimed subject matter. Thissummary is not an extensive overview, and is not intended to identifykey/critical elements or to delineate the scope of the claimed subjectmatter. Its sole purpose is to present some concepts in a simplifiedform as a prelude to the more detailed description that is presentedlater.

Systems and methods are provided to flexibly and efficiently map uplinkacknowledgement/negative-acknowledgement (ACK/NACK) responses in a timedivision duplex network. Various symbol mapping methods are providedthat account for asymmetric differences between downlink and uplinkchannel communications, where asymmetries occur when downlink subframesare greater than the number of uplink subframes. In one aspect, a symbolfirst mapping approach is provided. This includes ordering downlinkcontrol channels across downlink subframes having a first controlchannel element (CCE), located in a first symbol map, and associatedwith reserved resources for an uplink channel, where such resource caninclude resource blocks associate with ACK/NACK responses. After thefirst ordering, then ordering downlink control channels having a firstCCE in a second OFDM symbol followed by ordering downlink controlchannels having a first CCE in a third OFDM symbol and so forth asnecessary. In another aspect, a mixed-symbol, subframe first mapping canbe applied. Similar to the symbol first mapping, the subframe firstmapping includes ordering downlink control channels across downlinksubframes having a first control channel element (CCE), located in afirst symbol map, and associated with reserved resources for an uplinkchannel. The subframe first then orders remaining downlink controlchannels not associated with the first CCE in a first downlink subframe.This can be followed by ordering remaining downlink control channels notassociated with the first CCE or the first downlink subframe in a seconddownlink subframe and so forth.

To the accomplishment of the foregoing and related ends, certainillustrative aspects are described herein in connection with thefollowing description and the annexed drawings. These aspects areindicative, however, of but a few of the various ways in which theprinciples of the claimed subject matter may be employed and the claimedsubject matter is intended to include all such aspects and theirequivalents. Other advantages and novel features may become apparentfrom the following detailed description when considered in conjunctionwith the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a high level block diagram of a system that employs symbolmapping components to facilitate efficient allocation of resources in awireless communications system.

FIG. 2 is a block diagram that illustrates a symbol first mapping forefficient allocation of resources.

FIG. 3 is a block diagram that illustrates a mixed-symbol and subframefirst mapping for efficient allocation of resources.

FIG. 4 is a block diagram that illustrates a subframe first mapping forefficient allocation of resources.

FIG. 5 illustrates a wireless communications method that employs symbolmapping to facilitate efficient allocation of resources in a wirelesscommunications system.

FIG. 6 illustrates an example logical module for wireless symbolmapping.

FIG. 7 illustrates an example logical module for an alternative wirelesssymbol mapping process.

FIG. 8 illustrates an example communications apparatus that employswireless symbol mapping.

FIG. 9 illustrates a multiple access wireless communication system.

FIGS. 10 and 11 illustrate example communications systems.

DETAILED DESCRIPTION

Systems and methods are provided to efficiently allocate resourcesduring uplink acknowledgement/negative-acknowledgement (ACK/NACK)sequences. In one aspect, a method is provided to allocate resources forwireless communications. The method includes grouping downlink controlchannels from multiple subframes and ordering the downlink controlchannels across downlink subframes having a first control channelelement located in a first symbol map and associated with reservedresources for an uplink channel. The method employs a symbol firstmapping or a mixed-symbol/subframe first mapping to efficiently allocatethe resources.

Referring now to FIG. 1, symbol mapping components are employed tofacilitate efficient allocation of resources in a wirelesscommunications system 100. The system 100 includes one or more basestations 120 (also referred to as a node, evolved node B—eNB) which canbe an entity capable of communication over a wireless network 110 to asecond device 130 (or devices). For instance, each device 130 can be anaccess terminal (also referred to as terminal, user equipment, mobilitymanagement entity (MME) or mobile device). The base station 120communicates to the device 130 via downlink 140 (DL) and receives datavia uplink 150 (UL). Such designation as uplink and downlink isarbitrary as the device 130 can also transmit data via downlink andreceive data via uplink channels. It is noted that although twocomponents 120 and 130 are shown, that more than two components can beemployed on the network 110, where such additional components can alsobe adapted for the symbol mapping described herein. In one aspect, asymbol mapping component 160 is employed to order, sequence, or mapsymbols 170 and control allocation of resources such as ACK/NACKresources 180. The device 130 (or devices) includes a mapped symboldecoder 190 to process the mapped symbols 170 and resources 180. As willbe described in more detail below with respect to FIGS. 2-4, the symbolmapping component 160 can include a symbol first mapping method, amixed-symbol subframe first mapping method, or a subframe first mappingmethod. Before proceeding, it is noted that various acronyms areemployed for brevity. The acronyms are defined at the end of thespecification.

In general, UL resource allocation has to consider the number of UL andDL subframes. In one instance, consider, uplink ACK/NACK resourceallocation when n_(DL)≦n_(UL), where n_(DL) is number of downlinksubframes and n_(UL) is number of uplink subframes for a givenuplink-downlink configuration. The implicit mapping of UL ACK/NACK tothe first control channel element (CCE) of the DL PDCCH in TDD can beprocessed similarly as in FDD when n_(DL)≦n_(UL). Note that n_(DL)includes the special sub-frame(s). For UL ACK/NACK resource allocationwhen n_(DL)>n_(UL), then the asymmetric case is considered. In theasymmetric case, where the number of DL sub-frames is larger than the ULsub-frames, within one UL sub-frame, the UL ACK/NACK responds tomultiple DL sub-frames. Note the DL sub-frames include the specialsub-frame(s).

In general, the system 100 flexibly and efficiently maps uplinkacknowledgement/negative-acknowledgement (ACK/NACK) responses in a timedivision duplex network (can also be applied to FDD). Various symbolmapping methods are provided that account for asymmetric differencesbetween downlink and uplink channel communications, where asymmetriesoccur when downlink subframes are greater than the number of uplinksubframes. In one aspect, a symbol first mapping approach is provided.This includes ordering downlink control channels across downlinksubframes having a first control channel element (CCE), located in afirst symbol map, and associated with reserved resources for an uplinkchannel, where such resource can include resource blocks associate withACK/NACK responses. After the first ordering, then ordering downlinkcontrol channels having a first CCE in a second OFDM symbol followed byordering downlink control channels having a first CCE in a third OFDMsymbol and so forth as necessary. The symbol first mapping approach isdescribed in more detail with respect to FIG. 2.

In another aspect, a mixed-symbol, subframe first mapping can beapplied. Similar to the symbol first mapping, the subframe first mappingincludes ordering downlink control channels across downlink subframeshaving a first control channel element (CCE), located in a first symbolmap, and associated with reserved resources for an uplink channel. Thesubframe first then orders remaining downlink control channels notassociated with the first CCE in a first downlink subframe. This can befollowed by ordering remaining downlink control channels not associatedwith the first CCE or the first downlink subframe in a second downlinksubframe and so forth. The mixed-symbol subframe first mapping isdescribed in more detail with respect to FIG. 3. A subframe firstmapping is described with respect to FIG. 4.

It is noted that the system 100 can be employed with an access terminalor mobile device, and can be, for instance, a module such as an SD card,a network card, a wireless network card, a computer (including laptops,desktops, personal digital assistants (PDAs)), mobile phones, smartphones, or any other suitable terminal that can be utilized to access anetwork. The terminal accesses the network by way of an access component(not shown). In one example, a connection between the terminal and theaccess components may be wireless in nature, in which access componentsmay be the base station and the mobile device is a wireless terminal.For instance, the terminal and base stations may communicate by way ofany suitable wireless protocol, including but not limited to TimeDivisional Multiple Access (TDMA), Code Division Multiple Access (CDMA),Frequency Division Multiple Access (FDMA), Orthogonal Frequency DivisionMultiplexing (OFDM), FLASH OFDM, Orthogonal Frequency Division MultipleAccess (OFDMA), or any other suitable protocol.

Access components can be an access node associated with a wired networkor a wireless network. To that end, access components can be, forinstance, a router, a switch, or the like. The access component caninclude one or more interfaces, e.g., communication modules, forcommunicating with other network nodes. Additionally, the accesscomponent can be a base station (or wireless access point) in a cellulartype network, wherein base stations (or wireless access points) areutilized to provide wireless coverage areas to a plurality ofsubscribers. Such base stations (or wireless access points) can bearranged to provide contiguous areas of coverage to one or more cellularphones and/or other wireless terminals.

Turning to FIG. 2, a system 200 provides a symbol first mappingcomponent 210 for efficient allocation of resources. In general, PDCCH'sare ordered having a first control channel element (CCE) located in afirst OFDM symbol at 220. This is followed by PDCCH's that are orderedas a first control channel element (CCE) located in a second OFDM symbolat 230 and PDCCH's that are ordered as a first control channel element(CCE) located in a third OFDM symbol at 240 and so forth.

A subframe first approach (See FIG. 4) may end up with unused PUCCHresources or impose strict constraints at the scheduler at the cost ofinefficiently utilizing DL PDCCH resources. In order to overcome theseconstraints, a flexible alternative is provided and is referred to asthe OFDM Symbol First Mapping and is described as follows:

Group the DL PDCCHs in multiple-subframes together. As shown in FIG. 2,Re-order the PDCCHs in a manner such that the PDCCHs across the DLsubframes whose first CCE is located in the first OFDM symbol map to aband-edge of reserved resources for UL dynamic ACK/NACKs. This orderingis followed by the PDCCHs whose first CCE is located in the second OFDMsymbol and the PDCCHs whose first CCE is located in the third OFDMsymbol is mapped, and so forth. If some of the DL sub-frames do not useup N ACK/NACK resources (N a positive integer), with the OFDM symbolfirst mapping, some of the unused resources in the reserved band for ACKtransmissions can be scheduled by the eNB for PUSCH transmission.

Consider an M DL:1 UL (M is a positive integer) asymmetry pattern as anexample. Assume that in the first DL sub-frame, PDCCH region spans 3OFDM symbols while the other M−1 sub-frames use 2 OFDM symbols for PDCCHtransmission. Assume N ACK/NACK resources are needed to support PDCCHspan for 3 OFDM symbols with roughly N/3 for the PDCCH in each OFDMsymbol. The ACK resource reservation will assume 3 OFDM symboltransmission in each DL sub-frame as it is semi-static configured henceit has to cover the largest possible PDCCH time span for eachconfiguration period.

With the sub-frame first mapping, the first DL sub-frame will take upthe first N ACK/NACK resources; the second DL sub-frame cannot use upall N resources as the PDCCH span is 2 OFDM symbols instead of 3,however, the corresponding ACK resources cannot be freed up as theimplicit mapping of the third DL sub-frame assumes each DL sub-frame useup all N ACK resources. For the last DL sub-frame, the correspondingunused ACK resources can be used by PUSCH transmission as no furtherimplicit mapping is involved. With the OFDM symbol first mapping, the MDL sub-frames will take up the first N+2(M−1) N/3 ACK/NACK resources andthe remaining (M−1) N/3 resources are left unused and can be used forPUSCH transmission. However, with the OFDM symbol first mapping, if thefirst DL sub-frame utilizes 3 OFDM symbols to transmit PDCCH while forthe other DL sub-frames the PDCCH span is 1 OFDM symbol, some of the ACKresources can be wasted as in order to have the desired implicitmapping, the ACK resources corresponding to the PDCCHs whose first CCEis located in the second OFDM symbol cannot be freed up.

Referring to FIG. 3, a system 300 provides a mixed-symbol and subframefirst mapping component 310 for efficient allocation of resources.Similar to the first ordering describe in FIG. 2, PDCCH's are orderedhaving a first control channel element (CCE) located in a first OFDMsymbol at 320 which are followed by remaining PDCCH's in the first DLsubframe. At 330 and 340, remaining PDCCH's are ordered in second andthird DL subframes as necessary.

As mentioned above, the OFDM symbol first mapping can result in somepossible ACK resource inefficiencies and in this aspect, a mixedapproach is provided and denoted as “mixed OFDM symbol and sub-framefirst mapping.”

Initially, group the DL PDCCHs in multiple-subframes together. Similarto above, reorder these PDCCHs in a manner such that the PDCCHs acrossall DL sub-frames whose first CCE is located in first OFDM symbol map tothe band-edge of the reserved resources for UL dynamic ACK/NACKs. Thissequence can be followed by the remaining PDCCHs in the first DLsub-frame, the remaining PDCCHs in the second sub-frame and so on andshown at 330 and 340 respectively.

Consider the same M DL:1 UL asymmetry pattern as the example describedabove with respect to FIG. 2. Assume that in the first DL sub-framePDCCH region spans 3 OFDM symbols, while the other M−1 sub-frames use 1OFDM symbol for PDCCH transmission. Assume N ACK/NACK resources areneeded to support PDCCH span for 3 OFDM symbols with roughly N/3 for thePDCCH in each OFDM symbol. The ACK resource reservation assumes 3 OFDMsymbol transmissions in each DL sub-frame as it is semi-staticconfigured hence it has to cover the largest possible PDCCH time spanfor each configuration period.

With the sub-frame first mapping, the first DL sub-frame will take upthe first N ACK/NACK resources; the second DL sub-frame cannot use upthe N resources as the PDCCH span is 1 OFDM symbol instead of 3,however, the corresponding ACK resources cannot be freed up as theimplicit mapping of the third DL sub-frame assumes each DL sub-frameuses up N ACK resources. For the last DL sub-frame, the correspondingunused ACK resources can be used by PUSCH transmission as no furtherimplicit mapping is involved. With the OFDM symbol first mapping, the MDL sub-frames will utilize the first N+2(M−1) N/3 ACK/NACK resources andthe remaining (M−1) N/3 resources are left unused and can be used forPUSCH transmission. Note that even the M−1 sub-frames use 1 OFDM forPDCCH transmission instead of 2, thus the same number of ACK resourcesare employed. With the mixed approach, the M DL sub-frames will take upthe first N+(M−1) N/3 ACK/NACK resources and the remaining 2(M−1) N/3resources are left unused and can be used for PUSCH transmission.

Referring to FIG. 4, a system 400 illustrates a subframe first mappingcomponent 410 for allocation of resources. With the asymmetricconfiguration, each UL subframe will send ACK/NACK corresponding tomultiple sub-frames. The subframe first mapping approach maps the DLPDCCHs one sub-frame by one sub-frame as shown at 420 through 440respectively, i.e., the first DL sub-frame will take up the first NACK/NACK resources, then the second DL sub-frame, and so on. Dependingon the asymmetric configuration the UL ACK resource will be M times morethan needed in an FDD system where M is the asymmetric number (M DL vs 1UL).

In order to reduce the overhead, the total number of ACK resources canbe configured less than the total number of DL PDCCHs across multiple DLsub-frames. However, this would imply some of the PDCCH in one DLsub-frame will collide with some other PDCCHs in another subframe, hencethe schedule take the constraint into account. This would also imply thePDCCHs across different subframes may not be able to coexist hence acertain waste on the PDCCH resource is imposed. In another aspect, asthe number of PDCCHs in each DL subframe is a dynamic number dependingon PCFICH, the active users/buffer size in that sub-frame while the ULACK resource reservation is semi-static. Therefore, if some of the DLsub-frames do not use up the N ACK/NACK resources, the reservedbandwidth is not utilized.

Referring now to FIG. 5, a wireless communications methodology 500 isillustrated. While, for purposes of simplicity of explanation, themethodology (and other methodologies described herein) are shown anddescribed as a series of acts, it is to be understood and appreciatedthat the methodologies are not limited by the order of acts, as someacts may, in accordance with one or more embodiments, occur in differentorders and/or concurrently with other acts from that shown and describedherein. For example, those skilled in the art will understand andappreciate that a methodology could alternatively be represented as aseries of interrelated states or events, such as in a state diagram.Moreover, not all illustrated acts may be utilized to implement amethodology in accordance with the claimed subject matter.

Proceeding to 510, group the downlink control channels (e.g. PDCCH's)from multiple subframes. At 520, reorder the control channels such thatthe control channels across subframes having a first control channelelement (CCE) is located in a first OFDM symbol map to the band-edge ofthe reserved resources for uplink ACK/NACKs. After 520, at least threealternative processing approaches can be applied individually and/or indifferent combinations. At 530, a first processing approach employs anOFDM symbol first mapping as was previously described with respect toFIG. 2. At 540, an alternative processing approach utilizes a mixed OFDMsymbol and subframe first mapping as was described with respect to FIG.3. At 550, a third approach is a subframe first mapping process that canbe alternatively applied.

The techniques described herein may be implemented by various means. Forexample, these techniques may be implemented in hardware, software, or acombination thereof. For a hardware implementation, the processing unitsmay be implemented within one or more application specific integratedcircuits (ASICs), digital signal processors (DSPs), digital signalprocessing devices (DSPDs), programmable logic devices (PLDs), fieldprogrammable gate arrays (FPGAs), processors, controllers,micro-controllers, microprocessors, other electronic units designed toperform the functions described herein, or a combination thereof. Withsoftware, implementation can be through modules (e.g., procedures,functions, and so on) that perform the functions described herein. Thesoftware codes may be stored in memory unit and executed by theprocessors.

Turning now to FIGS. 6 and 7, a system is provided that relates towireless signal processing. The systems are represented as a series ofinterrelated functional blocks, which can represent functionsimplemented by a processor, software, hardware, firmware, or anysuitable combination thereof.

Referring to FIG. 6, a wireless communication system 600 is provided.The system 600 includes a logical module 602 for processing multiplecontrol channels from one or more subframes and a logical module 604 forsequencing the control channels across downlink subframes having a firstcontrol channel element located in a first symbol map and associatedwith reserved resources for an uplink channel. The system 600 alsoincludes a logical module 606 for generating a symbol first mapping or amixed-symbol/subframe first mapping to process the resources.

Referring to FIG. 7, a wireless communication system 700 is provided.The system 700 includes a logical module 702 for processing multiplecontrol channels from one or more subframes and a logical module 704 forreceiving the control channels from downlink subframes having a firstcontrol channel element located in a first symbol map and associatedwith reserved resources for an uplink channel. The system 700 alsoincludes a logical module 706 for processing a symbol first mapping or amixed-symbol/subframe first mapping to process the resources.

FIG. 8 illustrates a communications apparatus 800 that can be a wirelesscommunications apparatus, for instance, such as a wireless terminal.Additionally or alternatively, communications apparatus 800 can beresident within a wired network. Communications apparatus 800 caninclude memory 802 that can retain instructions for performing a signalanalysis in a wireless communications terminal. Additionally,communications apparatus 800 may include a processor 804 that canexecute instructions within memory 802 and/or instructions received fromanother network device, wherein the instructions can relate toconfiguring or operating the communications apparatus 800 or a relatedcommunications apparatus.

Referring to FIG. 9, a multiple access wireless communication system 900is illustrated. The multiple access wireless communication system 900includes multiple cells, including cells 902, 904, and 906. In theaspect the system 900, the cells 902, 904, and 906 may include a Node Bthat includes multiple sectors. The multiple sectors can be formed bygroups of antennas with each antenna responsible for communication withUEs in a portion of the cell. For example, in cell 902, antenna groups912, 914, and 916 may each correspond to a different sector. In cell904, antenna groups 918, 920, and 922 each correspond to a differentsector. In cell 906, antenna groups 924, 926, and 928 each correspond toa different sector. The cells 902, 904 and 906 can include severalwireless communication devices, e.g., User Equipment or UEs, which canbe in communication with one or more sectors of each cell 902, 904 or906. For example, UEs 930 and 932 can be in communication with Node B942, UEs 934 and 936 can be in communication with Node B 944, and UEs938 and 940 can be in communication with Node B 946.

Referring now to FIG. 10, a multiple access wireless communicationsystem according to one aspect is illustrated. An access point 1000 (AP)includes multiple antenna groups, one including 1004 and 1006, anotherincluding 1008 and 1010, and an additional including 1012 and 1014. InFIG. 10, only two antennas are shown for each antenna group, however,more or fewer antennas may be utilized for each antenna group. Accessterminal 1016 (AT) is in communication with antennas 1012 and 1014,where antennas 1012 and 1014 transmit information to access terminal1016 over forward link 1020 and receive information from access terminal1016 over reverse link 1018. Access terminal 1022 is in communicationwith antennas 1006 and 1008, where antennas 1006 and 1008 transmitinformation to access terminal 1022 over forward link 1026 and receiveinformation from access terminal 1022 over reverse link 1024. In a FDDsystem, communication links 1018, 1020, 1024 and 1026 may use differentfrequency for communication. For example, forward link 1020 may use adifferent frequency then that used by reverse link 1018.

Each group of antennas and/or the area in which they are designed tocommunicate is often referred to as a sector of the access point.Antenna groups each are designed to communicate to access terminals in asector, of the areas covered by access point 1000. In communication overforward links 1020 and 1026, the transmitting antennas of access point1000 utilize beam-forming in order to improve the signal-to-noise ratioof forward links for the different access terminals 1016 and 1022. Also,an access point using beam-forming to transmit to access terminalsscattered randomly through its coverage causes less interference toaccess terminals in neighboring cells than an access point transmittingthrough a single antenna to all its access terminals. An access pointmay be a fixed station used for communicating with the terminals and mayalso be referred to as an access point, a Node B, or some otherterminology. An access terminal may also be called an access terminal,user equipment (UE), a wireless communication device, terminal, accessterminal or some other terminology.

Referring to FIG. 11, a system 1100 illustrates a transmitter system1110 (also known as the access point) and a receiver system 1150 (alsoknown as access terminal) in a MIMO system 1100. At the transmittersystem 1110, traffic data for a number of data streams is provided froma data source 1112 to a transmit (TX) data processor 1114. Each datastream is transmitted over a respective transmit antenna. TX dataprocessor 1114 formats, codes, and interleaves the traffic data for eachdata stream based on a particular coding scheme selected for that datastream to provide coded data.

The coded data for each data stream may be multiplexed with pilot datausing OFDM techniques. The pilot data is typically a known data patternthat is processed in a known manner and may be used at the receiversystem to estimate the channel response. The multiplexed pilot and codeddata for each data stream is then modulated (i.e., symbol mapped) basedon a particular modulation scheme (e.g., BPSK, QPSK, M-PSK, or M-QAM)selected for that data stream to provide modulation symbols. The datarate, coding, and modulation for each data stream may be determined byinstructions performed by processor 1130.

The modulation symbols for all data streams are then provided to a TXMIMO processor 1120, which may further process the modulation symbols(e.g., for OFDM). TX MIMO processor 1120 then provides NT modulationsymbol streams to NT transmitters (TMTR) 1122 a through 1122 t. Incertain embodiments, TX MIMO processor 1120 applies beam-forming weightsto the symbols of the data streams and to the antenna from which thesymbol is being transmitted.

Each transmitter 1122 receives and processes a respective symbol streamto provide one or more analog signals, and further conditions (e.g.,amplifies, filters, and up-converts) the analog signals to provide amodulated signal suitable for transmission over the MIMO channel. NTmodulated signals from transmitters 1122 a through 1122 t are thentransmitted from NT antennas 1124 a through 1124 t, respectively.

At receiver system 1150, the transmitted modulated signals are receivedby NR antennas 1152 a through 1152 r and the received signal from eachantenna 1152 is provided to a respective receiver (RCVR) 1154 a through1154 r. Each receiver 1154 conditions (e.g., filters, amplifies, anddown-converts) a respective received signal, digitizes the conditionedsignal to provide samples, and further processes the samples to providea corresponding “received” symbol stream.

An RX data processor 1160 then receives and processes the NR receivedsymbol streams from NR receivers 1154 based on a particular receiverprocessing technique to provide NT “detected” symbol streams. The RXdata processor 1160 then demodulates, de-interleaves, and decodes eachdetected symbol stream to recover the traffic data for the data stream.The processing by RX data processor 1160 is complementary to thatperformed by TX MIMO processor 1120 and TX data processor 1114 attransmitter system 1110.

A processor 1170 periodically determines which pre-coding matrix to use(discussed below). Processor 1170 formulates a reverse link messagecomprising a matrix index portion and a rank value portion. The reverselink message may comprise various types of information regarding thecommunication link and/or the received data stream. The reverse linkmessage is then processed by a TX data processor 1138, which alsoreceives traffic data for a number of data streams from a data source1136, modulated by a modulator 1180, conditioned by transmitters 1154 athrough 1154 r, and transmitted back to transmitter system 1110.

At transmitter system 1110, the modulated signals from receiver system1150 are received by antennas 1124, conditioned by receivers 1122,demodulated by a demodulator 1140, and processed by a RX data processor1142 to extract the reserve link message transmitted by the receiversystem 1150. Processor 1130 then determines which pre-coding matrix touse for determining the beam-forming weights then processes theextracted message.

In an aspect, logical channels are classified into Control Channels andTraffic Channels. Logical Control Channels comprises Broadcast ControlChannel (BCCH) which is DL channel for broadcasting system controlinformation. Paging Control Channel (PCCH) which is DL channel thattransfers paging information. Multicast Control Channel (MCCH) which isPoint-to-multipoint DL channel used for transmitting MultimediaBroadcast and Multicast Service (MBMS) scheduling and controlinformation for one or several MTCHs. Generally, after establishing RRCconnection this channel is only used by UEs that receive MBMS (Note: oldMCCH+MSCH). Dedicated Control Channel (DCCH) is Point-to-pointbi-directional channel that transmits dedicated control information andused by UEs having an RRC connection. Logical Traffic Channels comprisea Dedicated Traffic Channel (DTCH) which is Point-to-pointbi-directional channel, dedicated to one UE, for the transfer of userinformation. Also, a Multicast Traffic Channel (MTCH) forPoint-to-multipoint DL channel for transmitting traffic data.

Transport Channels are classified into DL and UL. DL Transport Channelscomprises a Broadcast Channel (BCH), Downlink Shared Data Channel(DL-SDCH) and a Paging Channel (PCH), the PCH for support of UE powersaving (DRX cycle is indicated by the network to the UE), broadcastedover entire cell and mapped to PHY resources which can be used for othercontrol/traffic channels. The UL Transport Channels comprises a RandomAccess Channel (RACH), a Request Channel (REQCH), an Uplink Shared DataChannel (UL-SDCH) and plurality of PHY channels. The PHY channelscomprise a set of DL channels and UL channels.

The DL PHY channels comprises: Common Pilot Channel (CPICH),Synchronization Channel (SCH), Common Control Channel (CCCH), Shared DLControl Channel (SDCCH), Multicast Control Channel (MCCH), Shared ULAssignment Channel (SUACH), Acknowledgement Channel (ACKCH), DL PhysicalShared Data Channel (DL-PSDCH), UL Power Control Channel (UPCCH), PagingIndicator Channel (PICH), and Load Indicator Channel (LICH), forexample.

The UL PHY Channels comprises: Physical Random Access Channel (PRACH),Channel Quality Indicator Channel (CQICH), Acknowledgement Channel(ACKCH), Antenna Subset Indicator Channel (ASICH), Shared RequestChannel (SREQCH), UL Physical Shared Data Channel (UL-PSDCH), andBroadband Pilot Channel (BPICH), for example.

Other terms/components include: 3G 3rd Generation, 3GPP 3rd GenerationPartnership Project, ACLR Adjacent channel leakage ratio, ACPR Adjacentchannel power ratio, ACS Adjacent channel selectivity, ADS AdvancedDesign System, AMC Adaptive modulation and coding, A-MPR Additionalmaximum power reduction, ARQ Automatic repeat request, BCCH Broadcastcontrol channel, BTS Base transceiver station, CDD Cyclic delaydiversity, CCDF Complementary cumulative distribution function, CDMACode division multiple access, CFI Control format indicator, Co-MIMOCooperative MIMO, CP Cyclic prefix, CPICH Common pilot channel, CPRICommon public radio interface, CQI Channel quality indicator, CRC Cyclicredundancy check, DCI Downlink control indicator, DFT Discrete Fouriertransform, DFT-SOFDM Discrete Fourier transform spread OFDM, DL Downlink(base station to subscriber transmission), DL-SCH Downlink sharedchannel, D-PHY 500 Mbps physical layer, DSP Digital signal processing,DT Development toolset, DVSA Digital vector signal analysis, EDAElectronic design automation, E-DCH Enhanced dedicated channel, E-UTRANEvolved UMTS terrestrial radio access network, eMBMS Evolved multimediabroadcast multicast service, eNB Evolved Node B, EPC Evolved packetcore, EPRE Energy per resource element, ETSI European TelecommunicationsStandards Institute, E-UTRA Evolved UTRA, E-UTRAN Evolved UTRAN, EVMError vector magnitude, and FDD Frequency division duplex.

Still yet other terms include FFT Fast Fourier transform, FRC Fixedreference channel, FS1 Frame structure type 1, FS2 Frame structure type2, GSM Global system for mobile communication, HARQ Hybrid automaticrepeat request, HDL Hardware description language, HI HARQ indicator,HSDPA High speed downlink packet access, HSPA High speed packet access,HSUPA High speed uplink packet access, IFFT Inverse FFT, IOTInteroperability test, IP Internet protocol, LO Local oscillator, LTELong term evolution, MAC Medium access control, MBMS Multimediabroadcast multicast service, MBSFN Multicast/broadcast oversingle-frequency network, MCH Multicast channel, MIMO Multiple inputmultiple output, MISO Multiple input single output, MME Mobilitymanagement entity, MOP Maximum output power, MPR Maximum powerreduction, MU-MIMO Multiple user MIMO, NAS Non-access stratum, OBSAIOpen base station architecture interface, OFDM Orthogonal frequencydivision multiplexing, OFDMA Orthogonal frequency division multipleaccess, PAPR Peak-to-average power ratio, PAR Peak-to-average ratio,PBCH Physical broadcast channel, P-CCPCH Primary common control physicalchannel, PCFICH Physical control format indicator channel, PCH Pagingchannel, PDCCH Physical downlink control channel, PDCP Packet dataconvergence protocol, PDSCH Physical downlink shared channel, PHICHPhysical hybrid ARQ indicator channel, PHY Physical layer, PRACHPhysical random access channel, PMCH Physical multicast channel, PMIPre-coding matrix indicator, P-SCH Primary synchronization signal, PUCCHPhysical uplink control channel, and PUSCH Physical uplink sharedchannel.

Other terms include QAM Quadrature amplitude modulation, QPSK Quadraturephase shift keying, RACH Random access channel, RAT Radio accesstechnology, RB Resource block, RF Radio frequency, RFDE RF designenvironment, RLC Radio link control, RMC Reference measurement channel,RNC Radio network controller, RRC Radio resource control, RRM Radioresource management, RS Reference signal, RSCP Received signal codepower, RSRP Reference signal received power, RSRQ Reference signalreceived quality, RSSI Received signal strength indicator, SAE Systemarchitecture evolution, SAP Service access point, SC-FDMA Single carrierfrequency division multiple access, SFBC Space-frequency block coding,S-GW Serving gateway, SIMO Single input multiple output, SISO Singleinput single output, SNR Signal-to-noise ratio, SRS Sounding referencesignal, S-SCH Secondary synchronization signal, SU-MIMO Single userMIMO, TDD Time division duplex, TDMA Time division multiple access, TRTechnical report, TrCH Transport channel, TS Technical specification,TTA Telecommunications Technology Association, TTI Transmission timeinterval, UCI Uplink control indicator, UE User equipment, UL Uplink(subscriber to base station transmission), UL-SCH Uplink shared channel,UMB Ultra-mobile broadband, UMTS Universal mobile telecommunicationssystem, UTRA Universal terrestrial radio access, UTRAN Universalterrestrial radio access network, VSA Vector signal analyzer, W-CDMAWideband code division multiple access

It is noted that various aspects are described herein in connection witha terminal. A terminal can also be referred to as a system, a userdevice, a subscriber unit, subscriber station, mobile station, mobiledevice, remote station, remote terminal, access terminal, user terminal,user agent, or user equipment. A user device can be a cellulartelephone, a cordless telephone, a Session Initiation Protocol (SIP)phone, a wireless local loop (WLL) station, a PDA, a handheld devicehaving wireless connection capability, a module within a terminal, acard that can be attached to or integrated within a host device (e.g., aPCMCIA card) or other processing device connected to a wireless modem.

Moreover, aspects of the claimed subject matter may be implemented as amethod, apparatus, or article of manufacture using standard programmingand/or engineering techniques to produce software, firmware, hardware,or any combination thereof to control a computer or computing componentsto implement various aspects of the claimed subject matter. The term“article of manufacture” as used herein is intended to encompass acomputer program accessible from any computer-readable device, carrier,or media. For example, computer readable media can include but are notlimited to magnetic storage devices (e.g., hard disk, floppy disk,magnetic strips . . . ), optical disks (e.g., compact disk (CD), digitalversatile disk (DVD) . . . ), smart cards, and flash memory devices(e.g., card, stick, key drive . . . ). Additionally it should beappreciated that a carrier wave can be employed to carrycomputer-readable electronic data such as those used in transmitting andreceiving voice mail or in accessing a network such as a cellularnetwork. Of course, those skilled in the art will recognize manymodifications may be made to this configuration without departing fromthe scope or spirit of what is described herein.

What has been described above includes examples of one or moreembodiments. It is, of course, not possible to describe everyconceivable combination of components or methodologies for purposes ofdescribing the aforementioned embodiments, but one of ordinary skill inthe art may recognize that many further combinations and permutations ofvarious embodiments are possible. Accordingly, the described embodimentsare intended to embrace all such alterations, modifications andvariations that fall within the spirit and scope of the appended claims.Furthermore, to the extent that the term “includes” is used in eitherthe detailed description or the claims, such term is intended to beinclusive in a manner similar to the term “comprising” as “comprising”is interpreted when employed as a transitional word in a claim.

What is claimed is:
 1. A method to allocate resources for wirelesscommunications, comprising: grouping downlink control channels frommultiple subframes; mapping the downlink control channels to controlchannel elements (CCEs), wherein the mapping comprises ordering downlinkcontrol channels of the grouped downlink control channels in an effortto locate first CCEs of multiple downlink control channels to locationsthat implicitly map to a first set of resources reserved for uplink (UL)dynamic acknowledgement/negative-acknowledgment (ACK/NACK) such that asecond set of the resources reserved for UL dynamic ACK/NACK can be usedby physical uplink shared channel (PUSCH) transmission, wherein themapping comprises: ordering a first one or more downlink controlchannels, in an effort to locate first CCEs of the first one or moredownlink control channels to locations in a first subframe thatimplicitly map to the first set of resources; and ordering a second oneor more downlink control channels, of the grouped downlink controlchannels, in an effort to locate first CCEs of the second one or moredownlink control channels to locations in a second subframe thatimplicitly map to the first set of resources; ordering downlink controlchannels, of the grouped downlink control channels, not associated withthe first CCE in the first subframe for mapping to the first set ofresources; ordering downlink control channels, of the grouped downlinkcontrol channels, not associated with the first CCE or the firstsubframe, in the second subframe for mapping to the first set ofresources; and transmitting the downlink control channels in accordancewith the mapping.
 2. The method of claim 1, the downlink controlchannels are associated with a physical downlink control channels(PDCCHs).
 3. A communications apparatus, comprising: a memory thatretains instructions for: grouping downlink control channels frommultiple subframes; mapping the downlink control channels to controlchannel elements (CCEs), wherein the mapping comprises ordering downlinkcontrol channels of the grouped downlink control channels in an effortto locate first CCEs of multiple downlink control channels to locationsthat implicitly map to a first set of recourses reserved for uplink (UL)dynamic acknowledgment/negative-acknowledgement (ACK/NACK) such that asecond set of the resources reserved for UL dynamic ACK/NACK can be usedby physical uplink shared channel (PUSCH) transmission, wherein theinstructions for mapping comprise: ordering a first one or more downlinkcontrol channels, of the grouped downlink control channels, in an effortto locate first CCEs of the first one or more downlink control channelsto locations in a first subframe that implicitly map to the first set ofresources; and ordering a second one or more downlink control channels,of the grouped downlink control channels, in an effort to locate firstCCEs of the second one or more downlink control channels to locations ina second subframe that implicitly map to the first set of resources;ordering downlink control channels, of the grouped downlink controlchannels, not associated with the first CCE in the first subframe formapping to the first set of resources; ordering downlink controlchannels, of the grouped downlink control channels, not associated withthe first CCE or the first subframe, in the second subframe for mappingto the first set of resources; and transmitting the downlink controlchannels in accordance with the mapping; and a processor that executesthe instructions.
 4. A communications apparatus, comprising: means forgrouping downlink control channels from multiple subframes; means formapping the downlink control channels to first control channel elements(CCEs), wherein the mapping comprises ordering downlink control channelsof the grouped downlink control channels in an effort to locate firstCCEs of multiple downlink control channels to locations that implicitlymap to a first set of resources reserved for uplink (UL) dynamicacknowledgement/negative-acknowledgment (ACK/NACK) such that a secondset of the resources reserved for UL dynamic ACK/NACK can be used byphysical uplink shared channel (PUSCH) transmission, wherein the meansfor mapping comprises: means for ordering a first one or more downlinkcontrol channels, of the grouped downlink control channels, in an effortto locate first CCEs of the first one or more downlink control channelsto locations in a first subframe that implicitly map to the first set ofresources; and means for ordering a second one or more downlink controlchannels, of the grouped downlink control channels, in an effort tolocate first CCEs of the second one or more downlink control channels tolocations in a second subframe that implicitly map to the first set ofresources; mean for ordering downlink control channels, of the groupeddownlink control channels, not associated with the first CCE in thefirst subframe for mapping to the first set of resources; means forordering downlink control channels, of the grouped downlink controlchannels, not associated with the first CCE or the first subframe, inthe second subframe for mapping to the first set of resources; and meansfor transmitting the downlink control channels in accordance with themapping.
 5. A non-transitory computer-readable medium havinginstructions stored thereon, the instructions comprising code forcausing at least one computer to: group downlink control channels frommultiple subframes; map the downlink control channels across to controlchannel elements (CCEs), wherein the mapping comprises ordering downlinkcontrol channels of the grouped downlink control channels in an effortto locate first CCEs of multiple downlink control channels to locationsthat implicitly map to a first set of resources reserved for uplink (UL)dynamic acknowledgement/negative-acknowledgment (ACK/NACK) such that asecond set of the resources reserved for UL dynamic ACK/NACK can be usedby physical uplink shared channel (PUSCH) transmission; wherein themapping comprises: ordering a first one or more downlink controlchannels, of the grouped downlink control channels, in an effort tolocate first CCEs of the first one or more downlink control channels tolocations in a first subframe that implicitly map to the first set ofresources; and ordering a second one or more downlink control channels,of the grouped downlink control channels, in an effort to locate firstCCEs of the second one or more downlink control channels to locations ina second subframe that implicitly map to the first set of resources;ordering downlink control channels, of the grouped downlink controlchannels, not associated with the first CCE in the first subframe formapping to the first set of resources; ordering downlink controlchannels, of the grouped downlink control channels, not associated withthe first CCE or the first subframe, in the second subframe for mappingto the first set of resources; and transmit the downlink controlchannels in accordance with the mapping.